SAE-AMS-2451-12-2002-R2007.pdf

SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright © 2007 SAE International All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER:Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS:http:/www.sae.org Plating, Brush, Tin 1.SCOPE: 1.1Purpose: This specification covers the engineering requirements and process for brush plating of tin by electrodeposition. It shall be used, in conjunction with AMS 2451, for general-purpose tin deposits. 1.2Application: This process has been used typically to prevent galling or seizing of metal surfaces, to provide a surface for soft soldering, or to improve corrosion resistance, but usage is not limited to such applications. 1.3Safety - Hazardous Materials: See AMS 2451. 2.APPLICABLE DOCUMENTS: See AMS 2451. 3.TECHNICAL REQUIREMENTS: The requirements of AMS 2451 shall apply as herein amended. 3.1Procedure: 3.1.1Except as required in 3.1.1.1 or 3.1.2, tin shall be electroplated directly on the basis metal from a suitable brush plating solution in accordance with processing instructions from the solution manufacturer. 3.1.1.1For aluminum and aluminum alloys, a zinc immersion preplate may be used. AEROSPACE MATERIAL SPECIFICATION AMS 2451/12 Issued2002-12 Reaffirmed2007-11 Copyright SAE International Provided by IHS under license with SAELicensee=MHI - NAGOYA related to 3944000/3944000013 Not for Resale, 01/23/2008 23:37:34 MSTNo reproduction or networking permitted without license from IHS -,-,- AMS 2451/12SAEAMS 2451/12 - 2 - 3.1.2Prior to electrodeposition of tin for solderability on aluminum or copper-zinc alloy parts, a copper plate shall be deposited to a thickness of 0.0002 to 0.0003 inch (5.1 to 7.6 µm). 3.2Properties: 3.2.1Thickness: Where “tin flash” is specified, plate thickness shall be approximately 0.0001 inch (2.5 µm). 3.3Solderability: When specified, solderability of the plating shall be in accordance with ASTM B 545. The method of test shall be as specified by purchaser. 3.4Continuity of Plating: When specified, plating on ferrous parts, having a plating thickness of 0.0004 inch (10 µm) or more, shall be subjected to the porosity test of ASTM B 545 and the result evaluated according to the procedure described. When specified, plating on copper and copper alloys shall be subjected to the porosity test for copper basis metal given in ASTM B 545: the specimens shall be considered to have failed if pores in the coating blacken by the polysulfide test. 4.QUALITY ASSURANCE PROVISIONS: See AMS 2451. 5.PREPARATION FOR DELIVERY: See AMS 2451. 6.ACKNOWLEDGEMENT: See AMS 2451. 7.REJECTIONS: See AMS 2451. 8.NOTES: The requirements of AMS 2451 shall apply as herein amended. 8.1When using tin plating for electronics and precision moving parts applications, the potential for formation of tin whiskers should be considered. Under certain circumstances, metal whiskers grow from surfaces of tin electrodeposits. The tin whiskers are electrically conductive and some have measured 40 to 80 millionths of an inch in diameter with lengths up to 0.375 inch. Whiskers can reduce the electrical resistance between surfaces or cause short circuits. In the case of precision moving parts, displaced whiskers can cause mechanical interference. Copyright SAE International Provided by IHS under license with SAELicensee=MHI - NAGOYA related to 3944000/3944000013 Not for Resale, 01/23/2008 23:37:34 MSTNo reproduction or networking permitted without license from IHS -,-,- AMS 2451/12SAEAMS 2451/12 - 3 - 8.2Plating thickness greater than 0.0003 inch (8 µm) may result in tearing and dewetting during reflow. 8.3The plating meeting the requirements of this specification will exhibit equivalent properties to plating produced in accordance with MIL-T-10727 and AMS 2408. 8.4Key Words: Selective plating, brush plating, tin deposit, corrosion resistance, solderability, galling PREPARED UNDER THE JURISDICTION OF AMS COMMITTEE “B” Copyright SAE International Provided by IHS under license with SAELicensee=MHI - NAGOYA related to 3944000/3944000013 Not for Resale, 01/23/2008 23:37:34 MSTNo reproduction or networking permitted without license from IHS -,-,-